European patent EP 758,615 describes an example of a device enabling a plurality of sunscreens of different indices or a sunscreen and an after-sun lotion, such as a moisturizing cream, to be made available in what appears to be a single package.
European patent application EP 427,609 describes a device including an adjustment member for varying the proportions in a mixture of two substances taken from respective reservoirs. The adjustment member is in the form of a rotary part that presses to a greater or lesser extent on a pump rod when a pushbutton is depressed. This device does not make it possible to dispense the substance contained in one or the other reservoir, for example, by a single adjustment member.
U.S. Pat. No. 5,971,210 describes a device that is relatively complex, having a mechanism that enables actuation of a pushbutton to be transformed into strokes of greater or shorter length for actuating pump rods.
The supplier Versadial of Marktoberdorf, Germany, also proposes a device having two pumps with control members that are actuated by a pivoting disk secured to the pushbutton and hinged at one end to an adjustment member capable of turning relative to a base portion that supports the pump bodies. Depending on the orientation of the adjustment member, when a user presses the pushbutton, the disk actuates the pump control members to a greater or lesser extent, thereby enabling a mixture to be dispensed with the desired relative proportions of the substances taken from the reservoirs associated with the pumps. Such a device is not designed to use standard pumps and is also of structure that is relatively complex.